<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    *{
        margin: 0 auto;
        padding: 0;
        font-family: sans-serif;
    }
    .user-box{
        position: relative;
        width: 100%;
        height: 400px;
        margin: 0 auto;
        /* text-align: center; */
        border: 1px solid #777;
        background: linear-gradient(#141e30, #243b55);
    }
    .UserName{
        width: 200px;
        height: 40px;
        position: absolute;
        top: 180px;
        left: 40%;
    }
    .username{
        position: absolute;
        top: 180px;
        left: 40%;
        z-index: 666;
        /* -ms-transition: all .5 ease; */
        transition: all .5s ease;

    }
    .UserName:focus~.username{
        top: 150px;
        font-size: 10px;
        color: azure;
    }
    .user-box a{
        position: absolute;
        top:270px;
        left: 45%;
        width: 100px;
        height: 50px;
        display: block;
        background-color: #141e30;
        color: aliceblue;
        text-align: center;
        line-height: 50px;
        text-decoration: none;
        overflow: hidden;
    }
    .user-box a:hover{
        box-shadow: 0 0 5px #03e9f4,
              0 0 25px #03e9f4;
              /* 0 0 50px #03e9f4, */
              /* 0 0 100px #03e9f4; */
    }
    .user-box a span{
        position: absolute;
        display: block;
    }
    .user-box a span:nth-child(1){
        top: 0;
        left: -100%;
        width: 100%;
        height: 2px;
        background: linear-gradient(90deg, transparent, #03e9f4);
        animation: btn-anim1 1s linear infinite;
    }
    @keyframes btn-anim1 {
        0%{
            left: -100%;
        }
        50%,100%{
            left: 100%;
        }
    }
    .user-box a span:nth-child(2){
        top: -100%;
        right: 0;
        width: 2px;
        height: 100%;
        background: linear-gradient(180deg, transparent, #03e9f4);
        animation: btn-anim2 1s linear infinite;
        animation-delay: .25s;
    }
    @keyframes btn-anim2 {
        0%{
            top: -100%;
        }
        50%,100%{
            top: 100%;
        }
    }
    .user-box a span:nth-child(3){
        bottom: 0;
        right: -100%;
        width: 100%;
        height: 2px;
        background: linear-gradient(270deg, transparent, #03e9f4);
        animation: btn-anim3 1s linear infinite;
        animation-delay: .5s;

    }
    @keyframes btn-anim3 {
        0%{
            right: -100%;
        }
        50%,100%{
            right: 100%;
        }
    }
    .user-box a span:nth-child(4){
        bottom: -100px;
        left: 0;
        height: 100%;
        width: 2px;
        background: linear-gradient(360deg, transparent, #03e9f4);
        animation: btn-anim4 1s linear infinite;
        animation-delay: .75s;

    }
    @keyframes btn-anim4 {
        0%{
            bottom: -100%;
        }
        50%,100%{
            bottom: 100%;
        }
    }
</style>
<body>
    <div class="user-box">
        <input type="text" class="UserName">
        <span class="username">UuserName</span>
        <a href="">
            <span></span>
            <span></span>
            <span></span>
            <span></span>
            submit
        </a>
    </div>
</body>
</html>